Nice one. I used to have an A1500 once. It had a Zorro FF/SD card for PC monitors, a GVP SCSI card with a hard drive with some extra RAM, a keyboard operated ROM switcher (1.3 & 2.0 ROMS - no 3.x back then) and a Zorro card with half a meg of RAM which I'd salvaged out of my A2000 when it caught fire (damn PSU).
Best thing you can do is get a flicker fixer, a couple of 3.1 ROMS and a Bhudda Zorro IDE controller. You can then slap a nice big (cheap) hard drive in there along with a CD ROM.... and don't forget OS3.9.
I wish they had put the A3000 desktop in the same A2000/A1500 case. I hate having my CD ROM drive in an external case :-(
check out Eyetech.co.uk and PowerC.com for parts.